On 1/16/20 10:43 AM, Nikola Forró wrote:
Order of parameters usually doesn't matter, but that's not the case with
memory.limit_in_bytes and memory.memsw.limit_in_bytes. When the latter
is first in the list of parameters, the resulting configuration is not
loadable with cgconfigparser.
Nice. Good find.
This happens because when a cgroup is created, both memory.limit_in_bytes
and memory.memsw.limit_in_bytes parameters are initialized to highest
value possible (RESOURCE_MAX). And because memory.memsw.limit_in_bytes
must be always higher or equal to memory.limit_in_bytes, it's impossible
to change its value first.
Make sure that after constructing parameter list of memory subsystem,
the mentioned parameters are in correct order.
Signed-off-by: Nikola Forró <nfo...@redhat.com>
---
src/api.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/src/api.c b/src/api.c
index c37855f..92730e6 100644
--- a/src/api.c
+++ b/src/api.c
@@ -2715,6 +2715,30 @@ int cgroup_get_cgroup(struct cgroup *cgroup)
}
}
closedir(dir);
+
+ if (! strcmp(cgc->name, "memory")) {
+ /*
+ * Make sure that memory.limit_in_bytes is placed before
+ * memory.memsw.limit_in_bytes in the list of values
+ */
+ int memsw_limit = -1;
+ int mem_limit = -1;
+
+ for (j = 0; j < cgc->index; j++) {
+ if (! strcmp(cgc->values[j]->name,
+
"memory.memsw.limit_in_bytes"))
+ memsw_limit = j;
+ else if (! strcmp(cgc->values[j]->name,
+
"memory.limit_in_bytes"))
+ mem_limit = j;
+ }
+
+ if (memsw_limit >= 0 && memsw_limit < mem_limit) {
+ struct control_value *val =
cgc->values[memsw_limit];
+ cgc->values[memsw_limit] =
cgc->values[mem_limit];
+ cgc->values[mem_limit] = val;
+ }
+ }
I feel like it would make sense to create a separate function with
these memory checks. cgroup_get_cgroup() is getting pretty long, and
splitting these changes out would make for better readability and
testability.
In fact, I prototyped that up quickly. Here are the two commits I
made for this:
https://github.com/drakenclimber/libcgroup/commit/bcf34c6fa7739f1dc69f190086e8ca398a8e42ab
https://github.com/drakenclimber/libcgroup/commit/f0faaa01600a30f593cbf7afd5328bc96452397f
And here's the code coverage. I was able to achieve 100% coverage!
https://coveralls.io/builds/28160581/source?filename=src/api.c#L2620
I believe the logic is functionally correct.
Thanks.
Tom
}
/* Check if the group really exists or not */
_______________________________________________
Libcg-devel mailing list
Libcg-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/libcg-devel
